Colon cancer is related to high beef/fat consumption. Broiling of beef or pyrolysis of proteins and aromatic amino acids have been shown to yield mutagens so that it seems possible that cooking of meat, leading to some pyrolysis of the outer surface, yields carcinogens responsible for these diet related cancers. We will determine the effect of the parameters of time, temperature and method of cooking, such as frying and broiling, upon the production of mutagens in meat. Meat surface scrapings, homogenized in DMSO, will be assayed for mutagenicity, using both the method of Ames with and without microsomal activation, and the method of Williams for induction of unscheduled DNA synthesis in rat liver cell culture. We will also purify mutagens found in meat scrapings. Using the purification scheme of Sugimura et al., we will demonstrate that the same mutagens they obtained from the pyrolysis of tryptophan are present after cooking meat. We have also devised a purification scheme to purify some other mutagens. We will also determine the amount of mutagen in the feces and urine of persons consuming their normal diet, broiled beef, boiled beef, and a vegetarian diet to determine if an increase in mutagen content occurs while eating broiled beef. In addition, using the purification techniques for the isolation of mutagen from cooked meat, comparison of elution profiles of mutagen from the purification, and from urine and fecal samples obtained from participants in the diet study, will give presumptive data showing whether or not mutagens from broiled beef are present in the urine and feces.